Asymmetric IR Illuminator Optics for Wide-Angle Vehicle Cameras
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Solution Overview
Problem
Vehicle camera systems face challenges in capturing clear images under low light and nighttime conditions due to limited field of view and interference from infrared radiation emitted by illuminators, which can enter the camera lens and affect image quality.
Innovation Solution
An infrared (IR) illuminator design with an elliptical cover lens and asymmetric radiation distribution is used to increase the field of view while preventing IR radiation from entering the camera lens, utilizing a combination of optical design, placement, and orientation to maintain high optical efficiency and radiation uniformity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If a symmetric radiation pattern is used for IR illuminator, then the radiation is evenly distributed, but the IR radiation enters the camera lens and degrades image quality
Solution Approach 1:
The patent applies asymmetry by designing the radiation pattern to be non-uniform, with intentionally reduced intensity in the direction of the camera lens. This asymmetric distribution allows the illuminator to provide sufficient IR lighting coverage while preventing harmful IR radiation from entering the camera lens, thus resolving the contradiction between radiation uniformity and avoiding lens interference.
2Area of stationary object
If the field of view is increased to capture more scene, then more area is illuminated, but IR radiation from illuminator enters the lens and affects image quality
Solution Approach 1:
The patent implements local quality by creating different radiation intensities in different spatial directions. The radiation pattern is designed to have higher intensity in directions away from the camera lens and lower intensity toward the lens, allowing broad area illumination while locally suppressing harmful radiation near the lens.
3Area of stationary object
If wide-angle lens is used to capture more scene, then the field of view is increased, but the lens is more susceptible to weather conditions and damage
Solution Approach 1:
The patent converts the potential harm of wide-angle lens vulnerability into a benefit by using asymmetric radiation patterning. The reduced IR intensity direction is strategically oriented toward the lens area, protecting it from harmful radiation while the wide field of view remains functional for capturing the scene.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The IR illuminator design enhances lighting within the camera's field of view, increasing the radiation pattern to beyond +/â80 degrees with improved uniformity, reducing clipping and maintaining image quality by avoiding interference with the camera lens.
Implementation Method 1
a cover lens positioned to cover the at least one IR LED. The cover lens changes IR radiated by the IR LED from a symmetric pattern into an asymmetric pattern
Data Source
AI summary
An IR illuminator provides infrared radiation for a digital camera that includes a camera lens including a camera field of view; also including equidistant mounting substrates arranged adjacent to the digital camera with IR LEDs mounted to each mounting substrates and a cover lens positioned over the IR LEDs. The free-form cover lens shape facilitates an emitted radiation emission pattern but prevents visible light reflectivity into the camera lens such that the IR radiation emission pattern has an asymmetric field of view. Two IR illuminators near the camera are angled away from the camera optical direction. The cover lens may be a Fresnel lens, may include a diffractive layer or a collimator to shift radiation emitted from the LED towards an asymmetric distribution.